Milky Way starfield in Cygnus at 2014mm FL

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Menno555
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Milky Way starfield in Cygnus at 2014mm FL

#1

Post by Menno555 »

Last week I realized that I never really focused on the most abundant objects arounds: stars. And also that I never really see captures of that with a long focal length scope. So I used Stellarium to look for a starfield without any other objects, dust or other features. This one came close.

This is 2 hours of data at f/10 (2014mm actual focal length). For reference: in this FOV the moon would just not fit.
This starfield is in the "head" of Cygnus.
The somewhat bright star on the right of the middle is HD 332436, a star of around MAG10. There are 3 galaxies in this FOV but to faint to see here.
Also not visible are some edges of dust clouds here but too faint and big to capture from here.
There are some "lanes" visible but those are areas with fewer stars from our viewpoint. Just like with M31 and its "propeller". If you squint a bit with your eyes, they become a bit more visible. The on its side V-shaped structure in the middle is most obvious.

And I used SiriL to count the stars. With the best settings for it, SiriL did count a bit over 23000 stars in this FOV. But the most faint and smallest stars weren't detected. So my estimate is that the amount of visible stars here is over 27000!

The 4000px version can be seen here: https://i.ibb.co/ZgvbhVL/Sterren-RGB.jpg
Sterren_RGBsm.jpg
Sterren_RGBsm.jpg (483.44 KiB) Viewed 101 times

Bortle 6/7
Meade LX200 8" f/10 ACF OTA
Ioptron CEM25EC mount (no guiding)
Baader IR/UV Cut filter
Zwo ASI071MC Pro camera

Captured with SharpCap Pro @ -10 Celsius / White balance R50 B50
20 x 300sec / Gain 20 / Offset 4
30 x darks, 50 x flats and 50 x darkflats per set

Stacked with SiriL and Sirilic

Processed with Siril and Photoshop
Siril: Crop, Photometric Color Calibration, Histogram
Photoshop: Camera Raw Filter (white balance, contrast, darks, color saturation, lightness, sharpening), light noise reduction NoiseXterminator plug-in.
timh
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Re: Milky Way starfield in Cygnus at 2014mm FL

#2

Post by timh »

Nice colour and exposure Menno. Some of the bigger dark regions possibly dark nebulae - or are they all just gaps? Tim
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Menno555
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Re: Milky Way starfield in Cygnus at 2014mm FL

#3

Post by Menno555 »

Thanks Tim.
There is not much to be found online on this small region. So I used Aladin and looked with a couple of catalogues. There are no nebulae there, only dust and that's faint and widespread.
I also used some IR catalogues like the Spitzer IR catalogue and there the same regions/lanes are visible. Assuming that the IR would "look through" those areas, I would expect more stars there in IR but there aren't.
Here a wider screenshot from Stellarium with my FOV outlined.

Menno

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timh
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Re: Milky Way starfield in Cygnus at 2014mm FL

#4

Post by timh »

Thanks for that bit of further research Menno. Good point about the IR comparison. That is useful to know and new learning for me because I had always tacitly assumed that such darker gaps were probably due to dark nebulosity - but clearly not the case. Tim
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Menno555
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Re: Milky Way starfield in Cygnus at 2014mm FL

#5

Post by Menno555 »

It's no a 100% certainty Tim. But from what I could tell and find, it's the same visual effect as with the "propeller" in M13.
It's a perceptual (I think that's the term?) thing where our brains are always looking for structures in something: just a rondom field of points and for sure, our brains will "see" lanes, circles, crosses and so on :)

Menno
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